Delete session doesn't work well with window-mode on

[kdowolski]

1. It doesn't delete session (as we feed kill-session with whole name, not just session)
2. After operation it ignores window-mode setting and renders the view with just session names.

Maybe it could delete window rather than session? WDYT?

I am happy to open PR for that if you would like to!

[omerxx]

Hey @kdowolski I'm actually seeing the session getting removed in window mode, do you experience something different? In terms of killing just the window rather than the entire session, yes, I think that's preferable.

If you'd like to tweak things so that

1. the window gets killed rather than the entire session while running window mode
2. (if you want) keep window mode running after killing the window

I'll be happy to have it!